Hi Team,
I am posting this on customer behalf regarding TPS63710 simulation.
According to the customer, the simulation yielded some useful results, but inconsistently, since it somewhat unpredictably fails to reach a reasonable solution.
This application sets the output voltage at -3.5V, has a parallel LR damped filter between the converter LC and the load, drives a 400mA max load represented by a 8.75 ohm resistor.
In this design, it is desirable to take the feedback from the output of the LR damped filter, for best DC regulation, rather than the output of the converter LC. Simulation can help determine what filter characteristics are required for converter stability, in particular what damping is required, when taking the feedback from the filter.
There are several problems:
First, typical for IC models, simulation fails to find a DC operating point without auto converge.
Second, for capacitance at the Ccap at the CAP pin greater than 120nF, and sometimes for smaller values, the simulation either fails to find the DC output operating voltage at all or it fails in a particular way; after finding the operating voltage in 0.12mS of simulated time, the output decays back to 0V over the remainder of the 1mS simulated time.
Also, the output reaches the DC operating voltage in 0.12mS of simulated time regardless of the value of Ccap.
Third, the simulation sporadically fails to find the DC output operating voltage.
In the diagram below, L4 is shorted to temporarily change the output filter to a simple damped LCR
Please let me know your comment.
Thanks.
Jonathan
